Cleaning method

ABSTRACT

Implementations of the present disclosure generally relate to methods and apparatuses for epitaxial deposition on substrate surfaces. More particularly, implementations of the present disclosure generally relate to methods and apparatuses for surface preparation prior to epitaxial deposition. In one implementation, a method of processing a substrate is provided. The method comprises etching a surface of a silicon-containing substrate by use of a plasma etch process, where at least one etching process gas comprising chlorine gas and an inert gas is used during the plasma etch process and forming an epitaxial layer on the surface of the silicon-containing substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority to U.S. provisional patentapplication Ser. No. 62/222,097, filed Sep. 22, 2015, and U.S.provisional patent application Ser. No. 62/232,810, filed Sep. 25, 2015.Both of the aforementioned applications are incorporated herein byreference in their entirety.

BACKGROUND

Field

Implementations of the present disclosure generally relate to methodsand apparatuses for epitaxial deposition on substrate surfaces.

Description of the Related Art

Integrated circuits are formed in and on silicon and other semiconductorsubstrates. In the case of single crystal silicon, substrates are madeby growing an ingot from a bath of molten silicon, and then sawing thesolidified ingot into multiple wafers. An epitaxial silicon layer maythen be formed on the monocrystalline silicon wafer to form adefect-free silicon layer that may be doped or undoped. Semiconductordevices, such as transistors, are manufactured from the epitaxialsilicon layer. The electrical properties of the formed epitaxial siliconlayer will generally be better than the properties of themonocrystalline silicon substrate.

Surfaces of the monocrystalline silicon and the epitaxial silicon layerare susceptible to contamination when exposed to typical waferfabrication facility ambient conditions. For example, a native oxidelayer may form on the monocrystalline silicon surface prior todeposition of the epitaxial layer. Additionally, contaminants present inthe ambient environment may deposit on the monocrystalline surface. Thepresence of a native oxide layer or contaminants on the monocrystallinesilicon surface negatively affects the quality of an epitaxial layersubsequently formed on the monocrystalline surface. While presentcleaning methods remove some of the native oxides and contaminants fromthe monocrystalline silicon surface, some contaminants still remain.

Therefore, there is a need for a method and apparatus for cleaning asubstrate surface, especially for cleaning a substrate surface prior toperforming an epitaxial deposition process.

SUMMARY

Implementations of the present disclosure generally relate to methodsand apparatuses for epitaxial deposition on substrate surfaces. Moreparticularly, implementations of the present disclosure generally relateto methods and apparatuses for surface preparation prior to epitaxialdeposition. In one implementation, a method of processing a substrate isprovided. The method comprises etching a surface of a silicon-containingsubstrate by use of a plasma etch process, where at least one etchingprocess gas comprising chlorine gas and an inert gas is used during theplasma etch process and forming an epitaxial layer on the surface of thesilicon-containing substrate. The inert gas is selected from argon,helium, or both. In one implementation, the plasma etch process utilizesan inductively coupled plasma etch process. In one implementation, themethod further comprises removing oxides from the surface of thesilicon-containing substrate by a cleaning process prior to etching thesurface of the silicon-containing substrate. In one implementation, thecleaning process is selected from NF₃/NH₃ plasma-based processes,hydrofluoric (“HF”)/NH₃ based processes, wet-HF processes, or NF₃/NH₃inductively coupled plasma processes. In one implementation, the etchingthe surface of the silicon-containing substrate and forming an epitaxiallayer on the surface of the silicon-containing substrate are performedwithout exposing the substrate to atmosphere.

In another implementation, a method of processing a substrate isprovided. The method comprises removing oxides from a surface of asilicon containing substrate positioned in a first substrate-processingregion by a cleaning process. The cleaning process is selected from awet etch process, a first plasma etch process, and a sputter etchprocess. The method further includes etching the surface of thesilicon-containing substrate positioned in a second substrate-processingregion by use of a second plasma etch process, where at least oneetching process gas comprising chlorine gas and an inert gas is usedduring the plasma etch process and forming an epitaxial layer on thesurface of the silicon-containing substrate. The inert gas is selectedfrom argon, helium, or both.

In yet another implementation, a method of processing a substrate isprovided. The method comprises etching a surface of a silicon-containingsubstrate positioned in a substrate-processing region of a firstprocessing chamber by use of a plasma etch process, where at least oneetching process gas comprising chlorine gas and an inert gas is usedduring the plasma etch process. The inert gas is selected from argon,helium, or both. The method further includes transferring thesilicon-containing substrate from the first processing chamber to asecond processing chamber after the plasma etch process without exposingthe substrate to atmosphere between the etching the surface and theforming the epitaxial layer and forming an epitaxial layer on thesurface of the silicon-containing substrate in the second processingchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description ofthe implementations, briefly summarized above, may be had by referenceto implementations, some of which are illustrated in the appendeddrawings. It is to be noted, however, that the appended drawingsillustrate only typical implementations of this disclosure and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective implementations.

FIG. 1 is a flow chart illustrating a processing sequence in accordancewith one implementation of the present disclosure;

FIG. 2 is a cross sectional view of a cleaning chamber according toimplementations described herein;

FIG. 3 is a cross-sectional view of a processing chamber according toimplementations described herein;

FIG. 4 is a schematic top view of a processing system that can be usedto complete the processing sequence illustrated in FIG. 1 according toimplementations described herein;

FIG. 5 is a schematic top view of another processing system that can beused to complete the processing sequence illustrated in FIG. 1 accordingto implementations described herein;

FIG. 6 is a schematic top view of another processing system that can beused to complete the processing sequence illustrated in FIG. 1 accordingto implementations described herein; and

FIG. 7 is a schematic top view of another processing system that can beused to complete the processing sequence illustrated in FIG. 1 accordingto implementations described herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneimplementation may be beneficially incorporated in other implementationswithout further recitation. It is to be noted, however, that theappended drawings illustrate only exemplary implementations of thisdisclosure and are therefore not to be considered limiting of its scope,for the disclosure may admit to other equally effective implementations.

DETAILED DESCRIPTION

The following disclosure generally describes methods and apparatuses forepitaxial deposition on substrate surfaces. Certain details are setforth in the following description and in FIGS. 1-7 to provide athorough understanding of various implementations of the disclosure.Other details describing well-known structures and systems oftenassociated with epitaxial deposition and surface preparation ofsubstrate are not set forth in the following disclosure to avoidunnecessarily obscuring the description of the various implementations.

Many of the details, dimensions, angles and other features shown in theFigures are merely illustrative of particular implementations.Accordingly, other implementations can have other details, components,dimensions, angles and features without departing from the spirit orscope of the present disclosure. In addition, further implementations ofthe disclosure can be practiced without several of the details describedbelow.

Native oxides present on silicon-containing surfaces prior to processingand oxygen contaminants that contaminate the silicon-containing surfaceduring processing affect the quality of subsequently deposited epitaxiallayers and the final formed device. Implementations of the presentdisclosure provide systems and methods for reducing native oxides andoxygen contaminants present during device formation. In oneimplementation of the present disclosure methods of pre-cleaning asilicon-containing substrate prior to epitaxial deposition, whichresults in deposition of an improved epitaxial material are provided. Ithas been found by the inventors that clustering processing chambersthrough vacuum transfer reduces exposure to atmosphere andcorrespondingly reduces exposure to oxygen contaminants. For example,performing inductively coupled plasma chlorine etching of silicon priorto epitaxial deposition without breaking vacuum between etching anddeposition reduces exposure to oxygen contaminants. In someimplementations, a native oxide removal process (e.g., capacitivelycoupled plasma using NH₃/NF₃; inductively coupled plasma using NH₃/NF₃;chemical oxide removal—thermal combination of anhydrous HF+NH₃, orexposure to aqueous HF) is performed followed by a silicon-etchingprocess (e.g., ICP H₂/Cl₂ silicon etching) and an epitaxial depositionprocess. Since most native oxide removal processes are unstable andnative oxide starts regrowing on the silicon-containing surface uponexposure to atmosphere. Clustering the native oxide removal chamberalong with the etching of silicon and epitaxial deposition also leads toa reduction in oxygen contaminants.

Implementations described herein will be described below in reference tocleaning, etching and deposition processes that can be carried out usingsystems available from Applied Materials, Inc. of Santa Clara, Calif.Other tools capable of performing these cleaning, etching and depositionprocesses may also be adapted to benefit from the implementationsdescribed herein. In addition, any system enabling the cleaning, etchingand deposition processes described herein can be used to advantage. Theapparatus description described herein is illustrative and should not beconstrued or interpreted as limiting the scope of the implementationsdescribed herein.

FIG. 1 illustrates a processing sequence 100 in accordance with oneimplementation of the present disclosure. Optionally, the processingsequence 100 begins at operation 110. In operation 110, native oxides ona surface of a substrate are removed by a cleaning process. Thesubstrate may include a silicon-containing material and the surface mayinclude a material, such as silicon (Si), germanium (Ge) or silicongermanium alloys (SiGe). In some implementations, the Si, Ge, or SiGesurface may have an oxide layer, such as native oxide layer, disposedthereon. The substrate may be a semiconductor substrate with devicesformed thereon.

In one implementation, operation 110 is performed in a processing regionof a first processing chamber. In one implementation, the firstprocessing chamber is positioned on a cluster tool allowing for transferof the substrate without exposing the substrate to atmosphere (e.g., ina vacuum environment.) In another implementation, the first processingchamber is separate from the cluster tool such that the substrate isexposed to atmosphere during removal and/or transfer of the substrate.

Any suitable cleaning process that removes oxides from the substratewithout significantly damaging the substrate may be used. Suitablecleaning processes include sputter etch processes, plasma etchprocesses, wet etch processes, or combinations thereof. Exemplary wetetch processes include wet etch processes using hydrofluoric acid (HF).Exemplary cleaning processes include NF₃/NH₃ plasma-based processes, hothydrofluoric (“HF”)/NH₃ based processes, wet HF processes, or NF₃/NH₃inductively coupled plasma processes.

In one implementation, the plasma etch process involves the simultaneousexposure of a substrate to NF₃ and NH₃ plasma by-products. The plasmaetch process may be a capacitively coupled plasma (CCP) process or aninductively couple plasma (ICP) process. In one implementation, theplasma etch process is a remote plasma assisted dry etch process whichinvolves the simultaneous exposure of a substrate to NF₃ and NH₃ plasmaby-products. In one example, the plasma etch process may be similar toor may include a SiCoNi™ etch process that is available from AppliedMaterials, Inc. of Santa Clara, Calif. In some configurations that useremote plasma excitation of the gas species allows plasma-damage-freesubstrate processing. The remote plasma etch can be largely conformaland selective towards silicon oxide layers, and thus does not readilyetch silicon regardless of whether the silicon is amorphous, crystallineor polycrystalline. The remote plasma process will generally producesolid by-products, which grow on the surface of the substrate assubstrate material is removed. The solid by-products can be subsequentlyremoved via sublimation when the temperature of the substrate is raised.The plasma etch process results in a substrate surface havingsilicon-hydrogen (Si—H) bonds thereon. The plasma process may be acapacitively coupled plasma process or an inductively coupled plasmaprocess.

In one implementation, the plasma etch process is a capacitively coupledplasma (CCP) process. In one implementation, the plasma etch process mayinclude an NF₃ flow rate within a range of about 1 sccm to about 20sccm, such as about 5 sccm, as well as an NH₃ flow rate within a rangeof about 50 sccm to about 200 sccm, such as about 100 sccm. In oneimplementation, the plasma etch process may further include an inert gas(argon, helium, or both argon and helium) at an inert gas flow ratewithin a range of between about 100 sccm and about 1,000 sccm (e.g.,between about 200 sccm and about 500; between about 300 sccm and about400 sccm). The plasma etch process may be performed at a pressure ofbetween about 1 Torr and about 10 Torr (e.g., between about 2 Torr andabout 5 Torr, between about 4 Torr and about 5 Torr; or about 5 Torr).The plasma etch process may be performed at an RF power setting ofbetween about 20 Watts and about 50 Watts (e.g., between about 20 Wattsto about 40 Watts; between about 25 Watts to about 35 Watts, or about 30Watts) may be utilized to ionize the NF₃ and the NH₃. By-products maythen be sublimated from the surface of the substrate by annealing thesubstrate at a temperature of about 120 degrees Celsius or more forabout 5 seconds to about 100 seconds, such as about 60 seconds. Otherimplementations of fluorine based cleaning involve, reacting NH₃ gas andF₂ or anhydrous HF gas in either plasma or thermal heat to etch SiO₂native oxides. Examples of gas flow ratios would be between 1:1 to 1:20gas flow ratio of fluorine gas to NH₃ gas (between 1:1 to 10:1 gas flowratio of NF₃ to NH₃ gas; between 3:1 to 20:1 gas flow ratio of NF₃ toNH₃ gas; or between 3:1 to 10:1 gas flow ratio of NF₃ to NH₃ gas) attemperatures of 15 degrees Celsius to 130 degrees Celsius (e.g., 20degrees Celsius to 100 degrees Celsius).

In another implementation, the plasma etch process is an inductivelycoupled plasma process. The inductively coupled plasma etch processincludes an NF₃ flow rate within a range of about 1 sccm to about 20sccm, such as about 5 sccm, as well as an NH₃ flow rate within a rangeof about 50 sccm to about 200 sccm, such as about 100 sccm. In oneimplementation, the inductively coupled plasma etch process may furtherinclude an inert gas (argon, helium, or both argon and helium) at aninert gas flow rate within a range of between about 500 sccm and about1,0000 sccm (e.g., between about 1,000 sccm and about 5,000; or betweenabout 1,000 sccm and about 2,000 sccm). The plasma etch process may beperformed at a pressure of between about 100 mTorr and about 500 mTorr(e.g., between about 200 mTorr and about 500 mTorr, between about 400mTorr and about 500 mTorr; or about 500 mTorr). The plasma etch processmay be performed at an RF power setting of between about 100 Watts andabout 500 Watts (e.g., between about 200 Watts to about 400 Watts;between about 250 Watts to about 350 Watts, or about 300 Watts) may beutilized to ionize the NF₃ and the NH₃. By-products may then besublimated from the surface of the substrate by annealing the substrateat a temperature of about 120 degrees Celsius or more for about 5seconds to about 100 seconds, such as about 60 seconds. Examples of gasflow ratios would be between 1:1 to 1:20 gas flow ratio of NF₃ gas toNH₃ gas (between 1:1 to 10:1 gas flow ratio of NF₃ to NH₃ gas; between3:1 to 20:1 gas flow ratio of NF₃ to NH₃ gas; or between 3:1 to 10:1 gasflow ratio of NF₃ to NH₃ gas) at temperatures of 0 degrees Celsius to 50degrees Celsius (e.g., 20 degrees Celsius to 40 degrees Celsius).

In another implementation, the cleaning process is a chemical oxideremoval process including treatment with thermal NH₃ and anhydroushydrofluoric acid (HF). The chemical oxide removal process may beperformed at a pressure of between about 100 mTorr and about 2,000 mTorr(e.g., between about 200 mTorr and about 1,000 mTorr, between about 400mTorr and about 500 mTorr; or about 500 mTorr). Examples of flow ratioswould be between 1:1 to 1:10 flow ratio of NH₃ gas to anhydrous HF(between 1:1 to 5:1 gas flow ratio of NF₃ to anhydrous HF; or between1:1 to 2:1 flow ratio of NH₃ to anhydrous HF) at temperatures of 0degrees Celsius to 100 degrees Celsius (e.g., 20 degrees Celsius to 40degrees Celsius). In one implementation, the chemical oxide removalprocess may further include an inert gas (argon, helium, nitrogen orcombinations thereof) at an inert gas flow rate within a range ofbetween about 500 sccm and about 1,0000 sccm (e.g., between about 1,000sccm and about 5,000; or between about 1,000 sccm and about 2,000 sccm).

In another implementation, the substrate is exposed to a wet cleanprocess. The substrate may be cleaned using a wet cleaning process inwhich a cleaning solution, such as a HF-last type cleaning solution,ozonated water cleaning solution, hydrofluoric acid (HF) and hydrogenperoxide (H₂O₂) solution, or other suitable cleaning solution. Thecleaning solution may be heated.

In another implementation, a different cleaning process may be utilizedto clean the substrate surface. In one implementation, plasma containingAr and NF₃ is introduced into the processing chamber. In anotherimplementation, a remote plasma containing He and NF₃ is introduced intoa processing chamber through a gas distribution plate, such as ashowerhead. NH₃ may be directly injected into the chamber via a separategas inlet.

In one implementation, after operation 110, the substrate is removedfrom the first processing chamber and transferred to a second processingchamber where operation 120 is performed. In one implementation,operation 120 is performed in a processing region of the secondprocessing chamber. In one implementation, both operation 110 andoperation 120 are performed in the same processing chamber. In oneimplementation, the second processing chamber is positioned on a clustertool allowing for transfer of the substrate without exposing thesubstrate to atmosphere (e.g., in a vacuum environment.)

At operation 120, silicon is removed from the silicon-containingsubstrate. Any suitable process may be used to remove silicon from thesilicon-containing substrate. In one implementation, the silicon isremoved from the silicon-containing substrate using a silicon etchingprocess. The silicon etching process may be a plasma-based etchingprocess. The plasma-based etching process may be a capacitively coupledplasma process or an inductively coupled plasma process. In oneimplementation, the silicon etching process may be an over-etchingprocess to enhance the surface of the substrate.

During the plasma-based etching process, an etching process gas isintroduced into the chamber. The etching process gas may comprise one ormore etch precursors. The etch precursors are delivered throughprecursor/gas inlets into a substrate processing region. In someimplementations, the etch precursors may be mixed prior to introductioninto the substrate processing region. In some implementations, etchprecursors may be introduced into the substrate processing regionsseparately. The etch precursors may excited by an inductively coupledplasma created by applying alternating current (AC) power to one or moreinductive coils. The etch precursor includes a halogen-containingprecursor, optionally a hydrogen-containing gas, and optionally an inertgas. In one implementation, the halogen-containing precursor is chlorinegas, the hydrogen-containing gas is hydrogen, and the optional inert gasis argon, helium, or both.

The halogen-containing precursor comprises a halogen or may comprise atleast one element from chlorine, bromine, and iodine. Thehalogen-containing precursor may be a chlorine-containing gas. Exemplarychlorine-containing gases include diatomic chlorine (Cl₂). The inert gasmay include at least one of argon, helium, neon, xenon and the like. Insome implementations, the substrate-processing region may consistessentially of chlorine, hydrogen and an inert gas, chlorine andhydrogen, halogen and an inert gas, or chlorine, hydrogen and argon. Theinclusion of the term “essentially” allows for other elementalconcentrations, which may be unavoidably present in a typical processingsystem, as well as low concentrations, which do not adversely affect thesilicon etching process.

Operation 120 includes applying energy to the halogen-containingprecursor, the optional hydrogen-containing precursor and the optionalinert gas if present to generate the radicals used to treat and etch thesurfaces of the substrate. The plasma may be generated using knowntechniques (e.g., radio frequency excitations, capacitively-coupledpower, inductively coupled power, and the like). In one implementation,the energy is applied using an inductively-coupled plasma power supplyunit. The power is supplied to the inductive coils shown incross-section in FIG. 3. The plasma power may be between about 25 wattsand about 2500 watts (e.g., between about 50 watts and about 2000 watts,between about 50 watts and about 500 watts; between about 100 watts andabout 400 watts, or between about 200 watts and about 300 watts). Thepressure in the substrate processing region may be between about 0.5mTorr and about 500 mTorr (e.g., between about 2 mTorr and about 200mTorr or between about 5 mTorr and about 100 mTorr; or between about 10mTorr and about 50 mTorr).

The RF frequency applied for either the local or remote plasmasdescribed herein may be low RF frequencies less than about 200 kHz, highRF frequencies between about 10 MHz and about 15 MHz, or microwavefrequencies greater than or about 1 GHz in embodiments.

The flow of the halogen-containing precursor may further include one ormore relatively inert gases such as He, N₂, Ar. The inert gas can beused to improve plasma stability, process uniformity and the like. Argonis helpful, as an additive, to promote the formation of a stable plasma.Process uniformity is generally increased when helium is included. Theseadditives are present in embodiments throughout this specification. Flowrates and ratios of the different gases may be used to control etchrates and etch selectivity.

In one implementation, the halogen-containing precursor (e.g. Cl₂) issupplied at a flow rate of between about 50 sccm (standard cubiccentimeters per minute) and 2 slm (e.g., between about 100 sccm andabout 1 slm; between about 100 sccm and 500 sccm; between about 200 sccmand 300 sccm). One of ordinary skill in the art would recognize thatother gases and/or flows may be used depending on a number of factorsincluding processing chamber configuration, substrate size, geometry andlayout of features being etched, and the like. With regard to operation120, the hydrogen-containing gas (e.g. H₂) may be supplied at a flowrate of between about 50 sccm (standard cubic centimeters per minute)and 2 slm (e.g., between about 100 sccm and about 1 slm; between about100 sccm and 500 sccm; between about 200 sccm and 300 sccm). Withfurther regard to operation 120, the inert gas (e.g. helium) may besupplied at a flow rate of between about 50 sccm (standard cubiccentimeters per minute) and 2 slm (e.g., between about 100 sccm andabout 1 slm; between about 100 sccm and 500 sccm; between about 200 sccmand 300 sccm). The temperature of the substrate may be between about −20degrees Celsius and about 200 degrees Celsius (e.g., between about 0degrees Celsius and about 100 degrees Celsius; between about 20 degreesCelsius and about 80 degrees Celsius) during operation 120.

In one implementation, the volumetric concentration of chlorine (Cl₂) inthe etching process gas may be less than about 10%, or, morespecifically less than about 5%, or even less than about 1% of the totalvolume of the etching process gas. In certain implementations, thevolumetric concentration of chlorine in the etching process gas isbetween about 1% and about 10% of the total volume of the etchingprocess gas.

In one implementation, the volumetric concentration of hydrogen (H₂) inthe etching process gas may be less than about 10%, or, morespecifically less than about 5%, or even less than about 1% of the totalvolume of the etching process gas. In certain implementations, thevolumetric concentration of chlorine in the etching process gas isbetween about 1% and about 10% of the total volume of the etchingprocess gas.

In one implementation, after operation 120, the substrate is removedfrom the second processing chamber and transferred to a third processingchamber where operation 130 is performed. In one implementation,operation 130 is performed in a processing region of the thirdprocessing chamber. In one implementation, both the second processingchamber and the third processing chamber are positioned on a clustertool allowing for transfer of the substrate from the second processingchamber to the third processing chamber without exposing the substrateto atmosphere (e.g., in a vacuum environment.) Not to be bound bytheory, but it is believed that exposure of the chlorine terminatedsilicon-containing surface, which is the result of operation 120, toatmosphere (e.g., an oxygen-containing environment) causes the oxygendose to increase 100 times on the chlorine terminated surface over afive minute period. As a result, it is preferable to perform operation120 and 130 without exposing the silicon-containing surface toatmosphere.

Next, at operation 130, an epitaxial layer is deposited on the surfaceof the substrate. The surface of the substrate is contaminant free,which improves the quality of the epitaxial layer subsequently formed onthe surface of the substrate. In one example, the epitaxial depositionmay be a selective epitaxial deposition process performed at atemperature that is less than 800 degrees Celsius. In this example, thetemperature is set such that it will not exceed 800 degrees Celsius, inorder to limit the wafer thermal budget for delicate features that maydistort or diffuse if overheated. In one embodiment, the epitaxial layeris deposited using a high temperature chemical vapor deposition (CVD)process. In this thermal CVD process, processing gases such asdichlorosilane, silane, disilane, germane, hydrogen chloride, orcombinations thereof are used to deposit the epitaxial layer. Theprocessing temperature is under 800 degrees Celsius and the processingpressure is between 5 and 600 Torr. When operations 110, 120 and 130 areperformed, contaminants at interfaces have been reduced and theepitaxial layer formed is relatively defect-free.

The epitaxial layer may be a silicon-containing layer, agermanium-containing layer, a Group III-V, or a Group IV material. Theepitaxial layer may be a binary film, ternary film, or quaternary film.Exemplary epitaxial layer materials include but are not limited tosilicon, germanium, GaN, AlN, AlGaN, InGaN, InAlGaN, GaAs,In_(x)Al_(1-x)As, In_(x)Ga_(1-x)As, InAs, Ge, Si_(1-x)Ge_(x), SiC, Si:C,Si:CP, SiGe:C, SiGe:B, GeSn, GaSb, GaP, InP, AlSb, AlP, AlSbP, MoSe₂,Ge_((1-x))Sn_(x), Si_((1-x-y))Ge_(x)Sn_(y) and combinations thereof, andmay be undoped or doped with an n-type or p-type dopant elementdepending upon application, or modified for additional properties, e.g.insulation, wherein 0<x,y<1 and 0<x+y<1. In some implementations, thebuffer layer is a material selected from the group consisting of: AlN,AlGaN, InGaN, InAlGaN, GaAs, InAlAs, Si, Ge, C, Sn, SiGe, SiC, GaSb,AlSb, GaP, AlP, InP, InSb, ZnO, WSe₂, MoSe₂, Ge_((1-x))Sn_(x),Si_((1-x-y))Ge_(x)Sn_(y) and combinations thereof wherein 0<x,y<1 and0<x+y<1. The epitaxial layer may be deposited using any suitableepitaxial deposition technique. Suitable epitaxial deposition techniquesinclude metal organic chemical vapor phase epitaxy (MOVPE) processes,hydride vapor phase epitaxial (HVPE) processes, Atomic Layer Epitaxy(ALE) and/or any other suitable process.

In some implementations, the epitaxial layer is a silicon germanium(SiGe) layer. During this deposition process a silicon precursor (e.g.,dichlorosilane) is flown concurrently into the processing chamber with acarrier gas (e.g., H₂ and/or N₂) and a germanium source (e.g., GeH₄).The flow rate of the silicon precursor may be in the range from about 5sccm to about 1,000 sccm. The flow rate of the silicon precursor may bein the range from about 100 sccm to about 500 sccm. The flow rate of thecarrier gas may be in the range from about 1,000 sccm to about 60,000sccm. The flow rate of the carrier gas may be in the range from about10,000 sccm to about 20,000 sccm. The flow rate of the germanium sourcemay be in the range from about 10 sccm to about 200 sccm. The flow rateof the germanium source may be in the range from about 50 sccm to about100 sccm. The processing chamber may be maintained with a pressure fromabout 0.1 Torr to about 200 Torr (e.g., from about 10 Torr to about 50Torr; about 20 Torr). The substrate may be kept at a temperature in therange from about 400 degrees Celsius to about 1,000 degrees Celsius(e.g., from about 500 degrees Celsius to about 600 degrees Celsius). Thereagent mixture is thermally driven to react and epitaxially deposit asilicon compound, namely a silicon germanium film on the substrate. Theprocess is conducted to form the SiGe layer with a thickness in a rangefrom about 100 Å to about 3,000 Å. The deposition rate may be betweenabout 50 Å/min and about 600 Å/min (e.g., between about 100 Å/min andabout 300 Å/min, about 150 Å/min). The germanium concentration is in therange from about 1 atomic percent to about 75 atomic percent of the SiGecompound (e.g., from about 50 atomic percent to about 70 atomic percent,about 65 atomic percent).

The silicon source is usually provided into the processing chamber at arate within a range from about 40 sccm to about 1,000 sccm (e.g., fromabout 200 sccm to about 800 sccm; from about 500 sccm to about 600sccm). Silicon sources that may be used for deposition of the strainrelaxed buffer layer include silanes, halogenated silanes, organosilanesor derivatives thereof. Silanes include silane (SiH₄) and higher silaneswith the empirical formula Si_(a)H_((2a+2)), such as disilane (Si₂H₆),trisilane (Si₃H₅) and tetrasilane (Si₄H₁₀), as well as others.Halogenated silanes include compounds with the empirical formulaX′_(b)Si_(a)H_((2a+2−b)), where X′ is independently selected from F, Cl,Br or I, such as hexachlorodisilane (Si₂Cl₆), tetrachlorosilane (SiCl₄),trichlorosilane (Cl₃SiH), dichlorosilane (Cl₂SiH₂) and chlorosilane(ClSiH₃). Organosilanes include compounds with the empirical formulaR_(b)Si_(a)H_((2a+2−b)), where R is independently selected from methyl,ethyl, propyl or butyl, such as methylsilane ((CH₃)SiH₃), dimethylsilane((CH₃)₂SiH₂), ethylsilane ((CH₃CH₂)SiH₃), methyldisilane ((CH₃)Si₂H₅),dimethyldisilane ((CH₃)₂Si₂H₄) and hexamethyldisilane ((CH₃)₆Si₂). Insome implementations, the silicon sources include silane, dichlorosilaneand disilane.

The germanium source gas may be provided at a rate of about 50 sccm toabout 500 sccm (e.g., about 80 sccm to about 200 sccm; about 90 sccm toabout 150 sccm; about 100 sccm). Germanium source gases may include oneor more of germane (GeH₄), higher germanes, or chlorinated germaniumderivatives, such as germanium dichloride (GeCl₂), germaniumtetrachloride (GeCl₄), or dichlorogermane (Cl₂GeH₂). Higher germanesinclude compounds with the empirical formula Ge_(x)H_((2x+2)), such asdigermane (Ge₂H₆), trigermane (Ge₃H₅) and tetragermane (Ge₄H₁₀), as wellas others.

The carrier gas is usually provided into the processing chamber at aflow rate within a range from about 1 slm to about 100 slm (e.g., fromabout 5 slm to about 80 slm; from about 10 slm to about 40 slm; about 20slm). Carrier gases may include nitrogen (N₂), hydrogen (H₂), argon,helium or combinations thereof. In one implementation, an inert carriergas is used. The inert carrier gas includes nitrogen, argon, helium orcombinations thereof. A carrier gas may be selected based on theprecursor(s) used and/or the process temperature of the depositionprocess.

FIG. 2 is a schematic cross sectional view of a processing chamber 200that may be adapted to perform operation 110. The processing chamber 200may be a cleaning chamber. The processing chamber 200 may beparticularly useful for performing a thermal or plasma-based oxidationprocess and/or a plasma assisted dry etch process. The processingchamber 200 includes a chamber body 212, a lid assembly 214, and asupport assembly 216. The lid assembly 214 is disposed at an upper endof the chamber body 212, and the support assembly 216 is at leastpartially disposed within the chamber body 212. A vacuum system can beused to remove gases from processing chamber 200. The vacuum systemincludes a vacuum pump 218 coupled to a vacuum port 221 disposed in thechamber body 212.

The lid assembly 214 includes at least two stacked components configuredto form a plasma volume or cavity there between. A first electrode 220is disposed vertically above a second electrode 222 confining a plasmavolume. The first electrode 220 is connected to a power source 224, suchas a radio frequency (RF) power supply, and the second electrode 222 isconnected to ground or a source return, forming a capacitance betweenthe first electrode 220 and the second electrode 222. The lid assembly214 also includes one or more gas inlets 226 for providing a cleaninggas to a substrate surface through blocker plate 228 and gasdistribution plate 230. The cleaning gas may be an etchant or ionizedactive radical, such as ionized fluorine, chlorine, or ammonia, or anoxidizing agent, such as ozone. Additionally, the processing chamber 200includes a controller 202 for controlling processes within theprocessing chamber 200.

The support assembly 216 may include a substrate support 232 to supporta substrate 210 thereon during processing. The substrate support 232 maybe coupled to an actuator 234 by a shaft 236, which extends through acentrally-located opening formed in a bottom surface of the chamber body212. The actuator 234 may be flexibly sealed to the chamber body 212 bybellows (not shown) that prevent vacuum leakage from around the shaft236. The actuator 234 allows the substrate support 232 to be movedvertically within the chamber body 212 between a process position and alower, transfer position. The transfer position is slightly below theopening of a slit valve formed in a sidewall of the chamber body 212.

The substrate support 232 has a flat, or a substantially flat, surfacefor supporting a substrate to be processed thereon. The substratesupport 232 may be moved vertically within the chamber body 212 byactuator 234 coupled thereto by shaft 236. In operation, the substratesupport 232 may be elevated to a position in close proximity to the lidassembly 214 to control the temperature of the substrate 210 beingprocessed. As such, the substrate 210 may be heated via radiationemitted or convection from the gas distribution plate 230.

A different cleaning process may be utilized to clean the substratesurface. In one embodiment, a remote plasma containing He and NF₃ isintroduced into a processing chamber through a gas distribution plate,such as a showerhead. NH₃ is directly injected into the chamber via aseparate gas inlet.

In one example of processing sequence 100, the clean process (operation110) may be performed in the SiCoNi™ cleaning chamber, available fromApplied Materials, Inc. of Santa Clara, Calif. Chambers available fromother manufacturers may also be used to practice implementationsdescribed herein. In one implementation, both operations 110 and 120 maybe performed in a single processing chamber, such as one of the chambersshown in FIGS. 2-3. In one implementation, both operations 110 and 120are performed in a SiCoNi™ cleaning chamber.

FIG. 3 is a cross sectional view of a plasma processing chamber 300according to implementations described herein. The plasma processingchamber 300 depicted in FIG. 3 includes an upper portion 328 and a lowerportion 330. The plasma-processing chamber 300 has a sidewall 305 and alid assembly 310. The sidewall 305 has an axially symmetrical shape,such as a cylinder. The sidewall 305 includes an axially symmetrical(e.g., cylindrical) dielectric side window 306 and a chamber liner 307,which may be formed of metal. A substrate support 315 inside the plasmaprocessing chamber 300 includes a pedestal 320 having a substratesupport surface 321 facing the lid assembly 310 for holding a substrate322, and a post 325 supporting the pedestal 320. The lid assembly 310,the pedestal 320 and the sidewall 305 confine a processing region 301 ofthe plasma-processing chamber 300. The pedestal 320 may include aninsulated internal electrode 324. Optionally, an electrostatic chucking(ESC) voltage and/or RF plasma bias power may be supplied to theinsulated internal electrode 324 via a cable 332 extending through thepost 325. The cable 332 may be coupled to an RF bias power source (suchas an RF impedance matching network and/or an RF power generator) as anRF bias feed to the insulated internal electrode 324. The cable 332 andmay be provided as a coaxial transmission line, which may be rigid (orflexible), or as a flexible coaxial cable.

Plasma source power is inductively coupled into the processing region301 by a set of coil antennas. The set of coil antennas includes aninner coil antenna 340, a middle coil antenna 350 and optionally anouter or side coil antenna 360, all of which are concentrically disposedwith respect to each other and are coaxial with the axis of symmetry ofthe sidewall 305. The lid assembly 310 includes a disk-shaped dielectricwindow through which the inner and middle coil antennas 340 and 350inductively couple RF plasma source power into the processing region301. The disk-shaped dielectric window 312 is coaxial with the sidewall305 and has a disk-plane parallel with the plane of the substratesupport surface 321. The side coil antenna 360 inductively couples RFplasma source power into the processing region 301 through thedielectric side window 306. The dielectric windows 306 and 312 may bereferred to collectively as a window assembly.

The chamber liner 307 is enclosed within a lower chamber body 370including a cylindrical lower chamber body sidewall 375 and a lowerchamber body floor 380. The cylindrical lower chamber body sidewall 375and the lower chamber body floor 380 enclose an evacuation region 381. Avacuum pump 390 is disposed in a vacuum pump opening 395 in the lowerchamber body floor 380 and is centered relative to the axis of symmetryof the cylindrical lower chamber body sidewall 375. A containment wall396 coaxial with the substrate support 315 and a flexible bellows 397extending between the pedestal 320 and the containment wall 396 enclosethe substrate support 315 in an internal central space 398. The internalcentral space 398 is isolated from the volume evacuated by the vacuumpump 390, including the evacuation region 381 and the processing region301.

The power may be supplied from a common RF source or from different RFsources such as RF matches (RF impedance matching networks) 342 and 344.An RF impedance matching network may be employed having dual outputs inorder to drive two of the coil antennas with a first RF generator, whilea second RF generator and a second RF impedance matching network drivesthe third coil antenna. Alternatively, three RF generators mayseparately drive the three coil antennas through three respective RFimpedance matching networks. In yet another embodiment, a single RFpower generator may drive all three coil antennas through an RFimpedance matching network having three outputs. In some implementationsof the foregoing embodiments, the RF power levels applied to thedifferent coil antennas may be separately adjusted in order to controlradial distribution of plasma ion density. While described embodimentsinclude the three coil antennas 340, 350 and 360, other embodiments mayinclude only one or two of the three described coil antennas 340, 350and 360.

Next, at operation 130, after the etching process is performed, anepitaxial silicon layer may be formed on the surface of the substrate asdescribe herein. The surface of the substrate is contaminant free, whichimproves the quality of the epitaxial layer subsequently formed on thesurface of the substrate. In one example, the epitaxial deposition maybe a selective epitaxial deposition process performed at a temperaturethat is less than 800 degrees Celsius. In this example, the temperatureis set such that it will not exceed 800 degrees Celsius, in order tolimit the wafer thermal budget for delicate features that may distort ordiffuse if overheated. In one embodiment, the epitaxial layer isdeposited using a high temperature chemical vapor deposition (CVD)process. In this thermal CVD process, processing gases such asdichlorosilane, silane, disilane, germane, hydrogen chloride, orcombinations thereof are used to deposit the epitaxial layer. Theprocessing temperature is under 800 degrees Celsius and the processingpressure is between 5 and 600 Torr. When operations 120 and 130 areperformed, contaminants at interfaces have been reduced and theepitaxial layer formed is relatively defect-free.

FIG. 4 illustrates a processing system 400 that can be used to completethe processing sequence 100 illustrated in FIG. 1, according toimplementations of the disclosure. One example of the processing system400 is the ENDURA® system available from Applied Materials, Inc., ofSanta Clara, Calif. As shown in FIG. 4, a plurality of processingchambers 402 is coupled to a first transfer chamber 404. The firsttransfer chamber 404 is also coupled to a first pair of processingchambers 406. The first transfer chamber 404 has a centrally disposedtransfer robot (not shown) for transferring substrates between theprocessing chambers 406 and the processing chambers 402. The processingchambers 406 are coupled to a second transfer chamber 410, which iscoupled to a cleaning chamber 414 for cleaning the substrate (operation110) and an etching chamber 416 for etching the substrate (operation120). The cleaning chamber 414 may be similar to processing chamber 200depicted in FIG. 2. The etching chamber 416 may be similar to plasmaprocessing chamber 300 depicted in FIG. 3. The second transfer chamber410 has a centrally disposed transfer robot (not shown) for transferringsubstrates between a set of load-lock chambers 412 and the cleaningchamber 414 or the etching chamber 416. A factory interface 420 isconnected to the second transfer chamber 410 by the load-lock chambers412. The factory interface 420 is coupled to one or more pods 430 on theopposite side of the load-lock chambers 412. The pods 430 typically arefront opening unified pods (FOUP) that are accessible from the cleanroom.

During operation, a substrate is first transferred to the cleaningchamber 414 where a cleaning process is performed to remove contaminantssuch as carbon or hydrocarbons from the substrate surface, breakthroughoxides formed on the surface of the substrate, or both. The cleaningprocess is described in FIG. 1 under operation 110. Then the substrateis transferred to the etching chamber 416 in which operation 120 isperformed.

The etched substrate is then transferred to one or more processingchambers 402 in which the epitaxial deposition, as described underoperation 130 is performed. Because all three operations 110, 120 and130 are performed within the same processing system, vacuum is notbroken as the substrate is transferred to various chambers, whichdecreases the chance of contamination and improves the quality of thedeposited epitaxial film.

FIG. 5 is a schematic top view of another processing system 500 that canbe used to complete the processing sequence illustrated in FIG. 1according to implementations described herein. In anotherimplementation, operation 110 is performed in a processing chamber 502that is not a part of the processing system that contains the etchingchamber 416 and the one or more processing chambers 402. As shown inFIG. 5, the substrate surface is cleaned in a processing chamber 502.The substrate is then transferred to the processing system 500, which isthe processing system 400 without the cleaning chamber 414. Thesubstrate is transferred to the etching chamber 416 in which operation120 is performed. Then the substrate is transferred to at least one ofthe processing chambers 402 in which operation 130 is performed.

FIG. 6 is a schematic top view of another processing system 600 that canbe used to complete the processing sequence illustrated in FIG. 1according to implementations described herein. One example of theprocessing system 600 is the CENTURA® system available from AppliedMaterials, Inc., of Santa Clara, Calif. A transfer robot 604 of anyconvenient type is disposed in a transfer chamber 602 of the processingsystem 600. A load-lock 606, with two load-lock chambers 606A, 606B iscoupled to the transfer chamber 602. A plurality of processing chambers608, 610, 612, 614, 616 are also coupled to the transfer chamber 602.The plurality of processing chambers 608, 610, 612, 614, 616 may includeat least one of a cleaning chamber, an etching chamber and depositionchambers, such as an epitaxial deposition chamber.

Processing chamber 608 may be a cleaning chamber configured to clean thesubstrate (operation 110) prior to deposition. The processing chamber608 may be configured to perform the Applied Materials SICONI™ Precleanprocess. The processing chamber 608 may be similar to processing chamber200 depicted in FIG. 2. The processing chamber 608 may be an etchingchamber for etching the substrate (operation 120). The processingchamber 608 may be similar to plasma processing chamber 300 depicted inFIG. 3. Processing chambers 610, 612, 614 may be a material depositionchamber such as an epitaxial deposition chamber capable of performing anepitaxial growth process.

The processing system 600 may be used to perform the processing sequence100 described above. During processing, a substrate that is to beprocessed may arrive to the processing system 600 in a pod (not shown).The substrate is transferred from the pod to the vacuum compatibleload-lock 606A, 606B by the factory interface robot (not shown). Thesubstrate is then handled by the transfer robot 604 in the transferchamber 602, which is generally kept in a vacuum state. The transferrobot 604 then loads the substrate into the processing chamber 608 forcleaning as described in operation 110. The transfer robot 604 thenpicks up the substrate from the processing chamber 608 and loads thesubstrate into the processing chamber 616 for etching as described inoperation 120. The transfer robot 604 then picks up the substrate fromthe processing chamber 608 and loads the substrate into the processingchamber 610, 612, whichever is available, for material deposition. Anepitaxial layer may be grown on the cleaned substrate in the processingchamber 610, 612, and 614 as described in operation 130.

FIG. 7 is a schematic view of another processing system 700 that can beused to complete the processing sequence illustrated in FIG. 1 accordingto implementations described herein. As shown in FIG. 7, the processingsystem 700 is a linear processing system with the processing chambers710, 720, 730 arranged in sequential order. The processing system 700has a transport system capable of moving the substrate through theprocessing regions of the various processing chamber. In oneimplementation, the transport system comprises one or more robotscapable of transferring the substrate. In another implementation, thetransport system comprises a common transport architecture. The commontransport architecture may comprise a track system, which extendsthrough the processing region or discrete processing regions and isconfigured to transport either a web substrate or discrete substrates.

Processing chamber 710 is a cleaning chamber for cleaning the substrate(operation 110). Processing chamber 710 may be similar to processingchamber 200 depicted in FIG. 2. Processing chamber 720 is an etchingchamber for etching the substrate (operation 120). Processing chamber720 may be similar to plasma processing chamber 300 depicted in FIG. 3.Processing chamber 730 is an epitaxial deposition chamber for depositionof materials onto the substrate (operation 130). Other components of theprocessing system 700 are not depicted for the sake of simplicity.

During operation, a substrate is first transferred to the processingchamber 710 where a cleaning process is performed to remove contaminantssuch as carbon or hydrocarbons from the substrate surface, breakthroughoxides formed on the surface of the substrate, or both. The cleaningprocess is described in FIG. 1 under operation 110. Then the substrateis transferred to the processing chamber 720 in which operation 120 isperformed.

The etched substrate is then transferred to processing chamber 730 inwhich the epitaxial deposition, as described under operation 130 isperformed. Because all three operations 110, 120, 130 are performedwithin the same processing system, vacuum is not broken as the substrateis transferred to various chambers, which decreases the chance ofcontamination and improves the quality of the deposited epitaxial film.

The transfer chambers may remain under vacuum and/or at a pressure belowatmosphere during the process. The vacuum level of the transfer chambersmay be adjusted to match the vacuum level of corresponding processingchambers. For example, when transferring a substrate from a transferchamber into a processing chamber (or vice versa), the transfer chamberand the processing chamber may be maintained at the same vacuum level.Then, when transferring a substrate from the transfer chamber to theload lock chamber or batch load lock chamber (or vice versa), thetransfer chamber vacuum level may match the vacuum level of the loadlockchamber or batch load lock chamber even through the vacuum level of theloadlock chamber or batch load lock chamber and the processing chambermay be different. Thus, the vacuum level of the transfer chamber may beadjusted. In certain implementations it may be desirable to backfill thetransfer chamber with an inert gas such as nitrogen. In oneimplementation, the substrate is transferred in an environment havinggreater than 90% N₂. In certain implementations, the substrate istransferred in a high purity NH₃ environment. In one implementation, thesubstrate is transferred in an environment having greater than 90% NH₃.In certain implementations, the substrate is transferred in a highpurity H₂ environment. In one implementation, the substrate istransferred in an environment having greater than 90% H₂.

It should be understood that the operations 110, 120, 130 of theprocessing sequence 100 may be performed using a series of stand-aloneprocessing chamber. In implementations where stand-alone processingchambers are used, the queue time between operations is managed toprevent some adverse effect on the fabricated device's performance.Queue time is generally defined as the time a substrate can be exposedto the atmospheric or other contaminants after a first process has beencompleted on the substrate before a second process is completed on thesubstrate to prevent some adverse effect on the fabricated device'sperformance. For example, in some implementations, the queue timebetween any of the operations 110, 120,130 may be between 1 hour and 12hours (e.g., between 8 to 12 hours; between 2 to 3 hours).

In implementations, where the operations 110, 120, 130 are performed instand-alone chambers, the substrate may be transferred between chambersin a separate carrier (not shown) in which an inert atmosphere (e.g.,nitrogen environment) is maintained.

In summary, some of the benefits of the present disclosure providemethods of pre-cleaning a silicon-containing substrate prior toepitaxial deposition, which results in epitaxial deposition of animproved epitaxial material. It has been found by the inventors thatclustering processing chambers through vacuum transfer reduces exposureto atmosphere and correspondingly reduces exposure to oxygencontaminants. For example, performing inductively coupled plasmachlorine etching of silicon prior to epitaxial deposition withoutbreaking vacuum between etching and deposition reduces exposure tooxygen contaminants. In some implementations, a native oxide removalprocess is performed followed by a silicon-etching process and anepitaxial deposition process. Since most native oxide removal processesare unstable and native oxide starts regrowing on the silicon-containingsurface upon exposure to atmosphere. Clustering the native oxide removalchamber along with the etching of silicon and epitaxial deposition alsoleads to a reduction in oxygen contaminants.

When introducing elements of the present disclosure or exemplary aspectsor implementation(s) thereof, the articles “a,” “an,” “the” and “said”are intended to mean that there are one or more of the elements.

While the foregoing is directed to implementations of the presentdisclosure, other and further implementations of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

1. A method of processing a substrate, comprising: etching a surface ofa silicon-containing substrate positioned in a substrate-processingregion by use of a plasma etch process, where at least one etchingprocess gas comprising chlorine gas and an inert gas is used during theplasma etch process; and forming an epitaxial layer on the surface ofthe silicon-containing substrate, wherein the inert gas is selected fromargon, helium, or both.
 2. The method of claim 1, wherein the plasmaetch process utilizes an inductively coupled plasma etch process.
 3. Themethod of claim 2, wherein the inductively coupled plasma etch processincludes forming an inductively coupled plasma by applying alternatingcurrent (AC) power to one or more inductive coils.
 4. The method ofclaim 1, wherein the etching the surface of the silicon-containingsubstrate and forming an epitaxial layer on the surface of thesilicon-containing substrate are performed without exposing thesubstrate to atmosphere.
 5. The method of claim 1, wherein the at leastone etching process gas further comprises hydrogen gas.
 6. The method ofclaim 1, wherein the volumetric concentration of chlorine gas is betweenabout 1% and about 10% of the total volume of the at least one etchingprocess gas.
 7. A method of processing a substrate, comprising: removingoxides from a surface of a silicon-containing substrate positioned in afirst substrate-processing region by a cleaning process, wherein thecleaning process is selected from a wet etch process, a first plasmaetch process, and a sputter etch process; etching the surface of thesilicon-containing substrate positioned in a second substrate-processingregion by use of a second plasma etch process, where at least oneetching process gas comprising chlorine gas and an inert gas is usedduring the plasma etch process; and forming an epitaxial layer on thesurface of the silicon-containing substrate, wherein the inert gas isselected from argon, helium, or both.
 8. The method of claim 7, whereinthe cleaning process is the first plasma etch process and the firstplasma etch process comprises simultaneous exposure of the surface ofthe silicon-containing substrate to NF₃ and NH₃ plasma by-products. 9.The method of claim 8, wherein the first plasma etch process is a remotecapacitively coupled plasma etch process.
 10. The method of claim 8,wherein the first plasma etch process is an inductively coupled plasmaetch process.
 11. The method of claim 10, wherein the inductivelycoupled plasma etch process includes forming an inductively coupledplasma by applying alternating current (AC) power to one or moreinductive coils.
 12. The method of claim 7, wherein the etching thesurface of the silicon-containing substrate and forming an epitaxiallayer on the surface of the silicon-containing substrate are performedwithout exposing the substrate to atmosphere.
 13. The method of claim 7,wherein the at least one etching process gas further comprises hydrogengas.
 14. The method of claim 7, wherein the volumetric concentration ofchlorine gas is between about 1% and about 10% of the total volume ofthe at least one etching process gas.
 15. A method of processing asubstrate, comprising: etching a surface of a silicon-containingsubstrate positioned in a substrate-processing region of a firstprocessing chamber by use of a plasma etch process, where at least oneetching process gas comprising chlorine gas and an inert gas is usedduring the plasma etch process; transferring the silicon-containingsubstrate from the first processing chamber to a second processingchamber after the plasma etch process without exposing the substrate toatmosphere between the etching the surface and the forming the epitaxiallayer; and forming an epitaxial layer on the surface of thesilicon-containing substrate in the second processing chamber, whereinthe inert gas is selected from argon, helium, or both.
 16. The method ofclaim 15, wherein the plasma etch process utilizes an inductivelycoupled plasma etch process.
 17. The method of claim 16, wherein theinductively coupled plasma etch process includes forming an inductivelycoupled plasma by applying alternating current (AC) power to one or moreinductive coils.
 18. The method of claim 15, wherein the at least oneetching process gas further comprises hydrogen gas.
 19. The method ofclaim 15, further comprising removing oxides from the surface of thesilicon-containing substrate in a third processing chamber prior toetching the surface of the silicon-containing substrate, by a cleaningprocess, wherein the cleaning process is selected from a wet etchprocess, a first plasma etch process, and a sputter etch process. 20.The method of claim 19, further comprising transferring thesilicon-containing substrate from the third processing chamber to thefirst processing chamber after the cleaning process without exposing thesubstrate to atmosphere between the cleaning process and the etching thesurface.